运行每 24 小时运行一次 swift 3

Question

我得到了一份报价清单，我正尝试根据日历每 24 小时更新一次。

这是我目前尝试的方法，但出现错误 无法将类型 'Date?' 的值转换为预期的参数类型 'TimeInterval'（又名 'Double'）

let numberOfQuotes = 3
let quotes = ["quote 1", "quote 2", "quote 3"]

override func viewDidLoad() {
    super.viewDidLoad()

    let timer = Timer.scheduledTimer(timeInterval: TimeInterval(30),
      target: self, selector: #selector(self.updateQuote), userInfo: nil,  repeats: true)
}

@objc func updateQuote() {
    let lastUpdate = UserDefaults.standard.object(forKey: "lastUpdate") as? Date
    if lastUpdate != nil {
        let date1:Date = Date() // Same you did before with timeNow variable
        let date2: Date = Date(timeIntervalSince1970: lastUpdate ) // **Getting error on this line**

        let calender:Calendar = Calendar.current
        let components: DateComponents = calender.dateComponents([.year, .month, .day, .hour, .minute, .second], from: date1, to: date2)

        if components.day! >= 1 {
            UserDefaults.standard.set(Date(), forKey: "lastUpdate")
         textView.text = "Hello there"
        }

    } else { //firstTime running
        UserDefaults.standard.set(Date(), forKey: "lastUpdate")
        textView.text = quotes[randomInt(min: 0,max: numberOfQuotes)]
    }
}

Answer 1

let date2: Date  = lastUpdate!

更新：

let components: DateComponents = calender.dateComponents([.year, .month, .day, .hour, .minute, .second], from: date2, to: date1)

Answer 2

lastUpdate 已经是 Date，初始值设定项 Date(timeIntervalSince1970: 是错误的，无论如何都不需要。

强烈建议使用可选绑定，并且不要注释编译器可以推断的类型。

if let lastUpdate = UserDefaults.standard.object(forKey: "lastUpdate") as? Date {
    let date1 = Date()

    let calender = Calendar.current
    let components = calender.dateComponents([.year, .month, .day, .hour, .minute, .second], from: date1, to: lastUpdate)
...

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